I need to run more current numbers, but a very tiny % of quitters are level 11 or higher (although lvl 11 and higher players often take a break from the game). Even the transition between Crest and Folrart (level 15) doesn't produce much of bump in quitters.

Actually they should also check and see if same email addresses were used.Also some people do move out of town once in a while. IP won't help that much.

It would be funny if the data points at a massive amount of abandoned alts.Anyways the reason they quit is obvious. Game has just the dull 1v1 arena and also has no serious events nor anything that makes guilds worthy, no minigames. etc etc etc